Dual textured pet foods have been known in the art for many years. U.S. Pat. No. 6,117,477 issued Sep. 12, 2000 discloses a dual textured food with a hard shell and a creamy filling wherein among other requirements, the shell contains less than 25% moisture. Within the disclosure of the ""477 patent, particularly at column 1, line 20 to column 2, line 42 are disclosed numerous patents relating to dual textured pet foods.
The problem of preparing a dual textured material which has all a pet""s daily nutrients in a form which is shelf stable, palatable and visually appealing is an ongoing issue. Such a composition has the capability of functioning as a delivery system for various functional, nutritional, and/or pharmaceutical ingredients.
A new process has now been discovered which can prepare a dual textured pet food having total nutritional value, if desired. The process features the preparation of the filling mixture in a heating vessel and the preparation of the hard shell in an extruder, the combining of the extruded shell and the filling in a die head which brings about the total enveloping of the filling with the shell and the exiting of the die head as a rope with the shell surrounding the filling followed by a severing of the rope into specific pieces of a desirable shape, for example, trapezoids, or pillow shapes.
Pet foods must contain all of a pet""s daily nutrients. The challenge in preparing a dual textured material is to assure it is shelf stable, palatable, visually appealing, and provides the minimum nutritional requirements without excess nutrients or ingredients that could be harmful. This is preferably accomplished by a unique die head which allows the extruded product to come off the die in a linear fashion. The shell flow module contains an individual shell flow regulator mechanism for each die hole which controls the pressure and, therefore, the flow of the shell material to be balanced to the individual die and from die to die as well. This assists in maintaining the desired nutritional profile of the diet. The shell filling module of the die is comprised of individual and separate nozzle like assemblies for each die opening. The individual nozzle openings are comprised of the nozzle body, die, core filling inlet connection and core outlet, any or all of which are configured to bring about specific advantages. The shell envelops the core as it exits the core outlet and form ropes. Additionally, the core outlet orifice is of such a projection into or even with the die taper of the die orifice and the core outlet orifice is of such a cross section that working together these two parameters provide a velocity of the shell composition exiting the die orifice which is closely matched to the velocity of the enveloped core composition. As the ropes exit the die opening, they are laid down on an upwardly inclined conveyor which advantageously prevents crossover, particularly when the die opening has affixed thereto conduits i.e., guide chambers which the ropes enter and which contain the ropes while they cool (set) and seem to lose to at least a significant extent their shear energy, thereby reducing the chance of rope crossover on the conveyor. The inclined conveyor further provides setting time prior to feeding the crimper/cutter. These and further advantages and aspects of the die will be elaborated upon later in the specification.
Other advantageous aspects of the invention are the nature of the filling as to physical appearance and chemical composition.
In accordance with the invention, there is a die head suitable for preparation of a dual textured pet food having a core and a shell surrounding or essentially surrounding the core, the die head attached to or an integral part of an extruder, which comprises
a) at least two shell flow areas through which an extruded shell composition flows,
b) a shell flow control regulator which is capable of impinging upon the shell flow,
c) a core inlet tube located post shell flow control regulator, its orifice in the shell flow, and delivering core composition to the shell flow wherein the shell composition essentially or totally envelops the core composition, and
d) the shell enveloped core composition exiting the die orifice.
A further aspect of the invention is a die head suitable for preparation of a dual textured pet food having a core and a shell surrounding or essentially surrounding the core, the die attached to or an integral part of an extruder which comprises:
a) at least two shell flow areas through which an extruded shell composition flows.
b) a core inlet tube, its orifice in the shell flow, the orifice of such a cross sectional size and located a distance from the die opening such that the velocity of the shell composition exiting the die opening is closely matched to the velocity of the core composition.
A still further aspect of the invention is a dual textured pet food wherein a shell completely or essentially envelops a core which comprises preparing a core composition in a vessel capable of being heated to at least about 140xc2x0 F., transferring core composition to a core inlet tube of a die head, preparing a shell composition of at least about 30 wt. % grains and mixing in a mixer, transporting to an extruder wherein the shell composition is subject to radial mixing, passing the core composition into a die head wherein the shell envelops or essentially envelops the core and exits the die head as a shell enveloped core.
The set back of the filling tube from the opening of the die is such as to allow flow of the shell material around the filling tube. This set back is approximately two times the diameter of the die opening but can vary from about 1.7 to about 2.3 times the diameter of the die opening. It should not be set back further than the end of the die taper.